Merge pull request #1432 from lybeen/doc/readme

chore: npm init with hint npm version

README.md

@@ -36,6 +36,7 @@ Create a new Rax project using `create-rax`:
 ```sh
 $ npm init rax <YourProjectName>
 ```
+_`npm init <initializer>` is available in npm 6+_
 
 Start local server to launch project: